As an example of heaters for use in the hair iron mentioned above or the like, a ceramic heater is disclosed in Japanese Unexamined Patent Publication JP-A 11-273837 (1999) (hereafter referred to as “Patent Literature 1”). The ceramic heater disclosed in Patent Literature 1 comprises: a ceramic substrate; a heater section disposed within the ceramic substrate; a lead section disposed within the ceramic substrate so as to be connected to the heater section; and an electrically conductive layer attached to the ceramic substrate, in which one end thereof is connected to the lead section and the other end thereof is led out to a surface of the ceramic substrate.
In the ceramic heater (hereafter also referred to simply as “heater”) disclosed in Patent Literature 1, however, heat generated in the heater section (heat-generating resistor) may be transmitted, through the lead section (conductor line), to a conductor layer (through-hole conductor). The heat trapped in the through-hole conductor may cause a thermal stress between the through-hole conductor and the ceramic substrate (ceramic structure). This makes it difficult to enhance the long-term reliability of the heater.